二级圆柱齿轮减速器速比分配规律探讨

以便于润滑、等接触疲劳强度为前提，推导出二级圆柱齿轮速比分配方程。利用计算机作出高速级传动比随总传动比的变化关系，采用最小二乘法，拟合出传动比分配的简便公式。     

变频器非正弦供电对异步电机运行性能的影响

分析了变频器电源供电的谐波分量及异步电机的谐波特性，推导出异步电机简化的谐波等效电路，并就谐波对异步电机运行性能的影响进行了探讨。     

调和级数sum from n=1 to ∞(1/n)的两条性质

本文利用调和级数的发散性 ,证明了调和级数的两条有趣而重要的性质 ,关于这两条性质更一般性的结论 ,本文还给出了一个猜想     

便携式电网谐波检测装置在电力系统中的应用

电能质量的好坏严重影响电力系统的稳定运行,测量和分析电能质量的装置运行可靠性对检测电网谐波的检测具有至关重要的作用。采用小波变换分析理论作为电网谐波检测和分析的方法,基于嵌入式linux操作系统和GUI图形界面,以S3C2410为核心,研究设计电网谐波检测装置,用以对谐波进行检测。     

西洋百合“卢浮宫”的组培技术研究

以鳞片为外植体、MS为基本培养基,以不同激素成分及不同质量浓度水平下诱导西洋百合"卢浮宫"的小鳞茎状突起,进行组培试验。结果表明:"卢浮宫"百合的诱导以取其完整的鳞片为外植体、并以鳞片背部突起处紧贴于MS+6-BA2.0mg·L-1+NAA0.2mg·L-1的培养基上诱导效果为最好。"卢浮宫"百合的诱导是由外植体(鳞片)产生小鳞茎状突起而分化成苗的,并不经愈伤组织分化产生。筛选出的最佳继代增殖培养基为MS+6-BA0.7mg·L-1+IBA0.3mg·L-1,生根培养基为1.2MS+6-BA0.3mg·L-1+IBA0 7mg·L-1。移植基质选择河泥和珍珠岩(体积比7∶3)混合,成活率达98%。     

Comparison of postoperative pain after ovariohysterectomy by harmonic scalpel-assisted laparoscopy compared with median celiotomy and ligation in dogs

OBJECTIVE: To compare the effects of postoperative pain after ovariohysterectomy by harmonic scalpel-assisted laparoscopy (HALO) and traditional ovariohysterectomy (OVH) in dogs. STUDY DESIGN: A randomized, blinded, prospective study. SAMPLE POPULATION: Sixteen, purpose-bred, intact female, Beagle dogs. METHODS: Dogs were divided into 2 groups: Group 1 (8 dogs), which had OVH by HALO, and Group 2 (8 dogs), which had traditional OVH. Physiologic data, abdominal nociceptive threshold scores, and University of Melbourne pain scores (UMPS) were recorded at 2, 6, 12, 24, 48, and 72 hours after surgery. Blood samples for measurement of plasma cortisol, glucose, and creatine phosphokinase (CPK) concentrations were collected at the time of the incision, and 2, 6, 12, 24, 48, and 72 hours after surgery. RESULTS: No significant surgical complications occurred. The HALO mean surgical time was significantly longer (55.7 minutes) than traditional OVH (31.7 minutes). No significant differences were observed between groups for the pain measures of heart rate, respiratory rate, temperature, CPK, and glucose concentrations. The OVH group had significantly higher mean plasma cortisol levels at hour 2 after surgery than the HALO group (P=.0001). The mean UMPS were significantly higher in OVH than the HALO group at all postoperative times (P=.0001). The mean nociceptive threshold measurements revealed significantly higher tolerated palpation pressures in HALO than OVH at all postoperative times, except hour 72 (P=.0002). CONCLUSIONS: Dogs appeared to be in less pain with HALO than OVH. The harmonic scalpel coagulated ovarian and uterine vessels completely with minimal collateral damage to surrounding tissues. CLINICAL RELEVANCE: HALO is a safe alternative to OVH and offers a minimally invasive and less painful method of surgery.     

补偿模糊神经网络水果形状分级器分级误差

针对神经网络对水果进行分级时精度有待提高的问题,分析了补偿模糊神经网络椪柑形状分级器的分级误差。将椪柑图像前4个傅里叶描述子按期望输出模糊变量值大小排列成单调递增、单调递减、钟形分布和锯齿形分布4种训练样本,分别训练同一补偿模糊神经网络水果形状分级器,用递减排序后的同一测试样本检验分级器性能,试验表明,单调递减顺序训练样本所训练的分级器分级误差最小为1.875%,钟形分布、单调递增顺序和锯齿形分布训练样本所训练的分级器分级误差依次增大,分别为15%、63.125%、75%。分析分级误差与样本间顺序的对应关系,建立分级误差模型,结果表明,同顺序的测试样本与训练样本间相关系数大,分级误差小;不同顺序的测试样本与训练样本间相关系数小,分级误差大。因此,测试样本与训练样本按水果同一品质特征同序排列,提高样本间的相关程度,将大幅度降低神经网络类分级器分级误差,提高正确识别率。     

黄家二岔小流域土壤水分空间分布特征

该文采用定位观测和谐波分析的方法对黄家二岔小流域土壤水分空间分布特征进行了研究．结果表明： 无论何种降雨年型, 流域内中游地段土壤含水量最高, 下游地段土壤含水量高于上游, 坡下部的高于坡上部, 阴坡高于阳坡．     

农电系统谐波电流检测及仿真环节的研究

准确、快速地检测农电系统电流的谐波成分是保证滤波器具备良好工作性能的关键。采用同步旋转park变换的d-q法对并联混合有源滤波器的谐波电流进行了检测,并进行了仿真分析。该方法不仅应用于三相平衡系统的谐波检测,也适合于电网电压有畸变和不对称情况下的检测。经实验和仿真,验证了该方法的准确性和实时性。     

垂直轴风力机塔柱结构的分析及优化

为了避免风力机系统的共振而导致的系统损坏和噪声污染,通过系统动力特性分析和动力学响应计算分析,得到了风力机塔柱的低阶固有频率和谐响应的数据,以及风轮和塔柱之间的动态关系与整个系统的动态特性,为结构动态设计以及优化提供科学依据.首先确定对风力机塔柱系统结构动态性能影响最大的模态频率,提取该阶模态频率作为动态优化的目标,最后分析塔柱结构与风轮之间的动态干扰.结果表明：原设计在风轮以设计额定转速160 r/min运行时,其产生的简谐荷载对风力机塔柱具有十分严重的破坏性,通过增加主轴钢管的壁厚并提高其刚度等优化工作,经计算证明,在激振力不变的情况下,第一阶固有频率得到提高,塔柱的各阶固有频率下的最大位移大幅减小,优化效果明显,达到结构动力设计的目的.